Pennsylvania Republican Tom Corbett, considered one of the most vulnerable incumbent governors in the country, trails Democratic challenger Tom Wolf by 20 percentage points five months ahead of November's election, a poll released on Wednesday showed.

Wolf, a businessman who poured his personal fortune into the four-way race for the Democratic nomination in May, leads Corbett 53 to 33 percent in the governor's race, according to a Quinnipiac University poll.

"There's no good news anywhere for Gov. Corbett," Tim Malloy, assistant director of the Quinnipiac Poll, said in a statement. "Gov. Tom Corbett looks like easy prey for Democratic challenger Tom Wolf."

Corbett has struggled with poor approval ratings for much of his first term as governor. The poll of 1,308 registered voters found that 55 percent disapprove of Corbett's performance while just a third of voters said he deserves to be re-elected.

Most poll respondents said the economy is in poor shape, and that Wolf would do a better job on education, the economy, jobs, energy, the environment and healthcare.

Wolf, a former Peace Corp volunteer who ran his family's cabinet-making business in the central Pennsylvania city of York, says he plans to restore funding the governor cut from education and favors a tax on natural gas drilling that Corbett has steadfastly opposed.

Just under half of poll respondents said they view Wolf favorably, while 14 percent do not and 38 percent say they do not know enough about him to form an opinion.

The poll was conducted from May 29 to June 2 and had a margin of error of plus or minus 2.7 percentage points.